Human Immunodeficiency Virus PowerPoint PPT Presentation

Introduction. H.I.V. stands for ?Human Immunodeficiency Virus".A retrovirus (capable of converting RNA into DNA by Reverse transcriptase enzyme)Causes A.I.D.S. (Acquired Immune Deficiency Syndrome) in humans in which the immune system of the body fails leading to life threatening opportunistic i

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Human Immunodeficiency Virus

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2. Introduction H.I.V. stands for “Human Immunodeficiency Virus”.
A retrovirus (capable of converting RNA into DNA by Reverse transcriptase enzyme)
Causes A.I.D.S. (Acquired Immune Deficiency Syndrome) in humans in which the immune system of the body fails leading to life threatening opportunistic infections and various un-usual tumors.

3. Introduction Discovered in 1984 and named HIV in 1986.
First reported in young homosexual males but later found in non-homosexuals possibly by blood transfusion.
HIV infects the Helper T (CD4) cells to which it binds

4. Types of H.I.V. Two types of HIV viruses exist:Type 1 and Type 2.
Both types causes AIDS which is clinically indistinguishable from each other and are transmitted by the same routes (discussed later in presentation)

5. Epidemiology

6. Epidemiology 33 Million people till 2007 have AIDS worldwide
2.0 Million (20 Lack) people died of AIDS worldwide in 2007
There has been reduction in this disease in US and western Europe however in developing countries this disease is rising.
In India only by 2006 were above 4 Million known cases of AIDS

7. Epidemiology According to WHO (2006) more than 25 Million people dead by AIDS since it's first recognition on December 1st 1981.
More than 570,000 children in 2005 died of AIDS.
In Africa more than 90 Million people are infected with HIV

9. Cells Targeted by HIV Three types of cells are targeted by HIV Virus.
(a ) Helper T cells (specifically CD4+ T cells).
(b )macrophages.
and (c ) dendritic cells.
Dendritic cells are the first cells encountered by HIV during sexual transmission when the virus is captured by dendritic cells in mucosa

11. Mechanism Of Action HIV enters macrophages and CD4+ T cells by the adsorption of glycoproteins on its surface to receptors on the target cell followed by fusion of the viral envelope with the cell membrane and the release of the HIV into the cell.
Repeated replication takes place (by enzyme reverse transcriptase) infects multiple CD4 cells resulting in extremely low levels of these cells

15. Stages Of Disease Tumors include: Cerebral lymphoma,non-Hodgkin's lymphoma, Kaposi's sarcoma
Pneumonia in this stage can be fatal
Neurological problems such as encephalopathy, neuropathy,retinitis,dementia may be present in 50% of cases

21. HIV tests are used to detect the presence of the human immunodeficiency virus in serum, saliva, or urine. Such tests may detect HIV antibodies, antigens, or RNA.
Tests employed are :
ELISA (Enzyme Linked Immunosorbent Assay)
Western Blot
Rapid or point-of-care test Investigations

22. ELISA detects antibodies to HIV-1. Non-reactive to ELISA are HIV negative and reactive ELISA specimens undergoes confirmatory testing with a more specific supplemental tests (Western Blot)
ELISA alone cannot be used to diagnose HIV positive case until confirmed by Western Blot
In ELISA we take patient's serum and make HIV antibodies. If HIV is present in the serum, antibodies bind to HIV and a change in color takes place
Investigations

23. In Western Blot, number of viral bands are indicative of result. If no bands present, then HIV negative
If 1 brand present of 3 proteins of HIV ( GAG, POL, and ENV ) then HIV +ve.
Polymerase Chain Reaction (PCR) . amplifies HIV DNA hence the amount of virus in the sample can be quantified with sufficient accuracy to detect changes.
Rapid or point-of-care tests should be used in conjunction with the clinical status, history, and risk factors of the person being tested
OraQuick is an antibody test that provides results in 20 minutes
Clearview Complete HIV 1/2 and Clearview HIV 1/2 Stat-Pakprovide results within 15 minutes
Investigations

24. The only known method of prevention is avoiding exposure to the virus.
However, a course of antiretroviral treatment administered immediately after exposure, referred to as post-exposure prophylaxis, is believed to reduce the risk of infection if begun as quickly as possible.
Anti-retroviral drugs such as :reverse transcriptase inhibitors (Zidovudine, Didanosine, Lamivdine), non-nucleoside reverse transcriptase inhibitors (Nevirapine, efavirens) and retroviral protease inhibitors (Indinavir, Ritonavir) are used currently.
HAART (Highly Active Anti-retroviral Therapy) includes use of 3 or more drugs
Treatment